Gaseous electric discharge device



April 2, 1940. o. FRITZE ET AL 2,195,517

GASEOUS ELECTRIC DISCHARGE DEVICE Filed Oct. 6, 1936 Otto Fritze lfredRuttenauer ORNEY Patented A r. 2, 1940 UNITED STATES PATENT OFFICEApplication October 6,

lin-Halensee, Germany, assignors to General Electric Company, acorporation of New York 1936, Serial No. 104,294

In Germany October 12, 1935 4 Claims.

The present invention relates to gaseous electric discharge devicesgenerally and more particularly the invention relates to such deviceshaving a luminescent material associated therewith to supplement andcomplement the light emitted by the gaseous electric discharge in thedevice.

In order to obtain a green colored light from a mercury vapor dischargelamp it is necessary to screen out of the light emitted by the dis-vcharge those rays other than the green colored rays. Heretofore this hasbeen accomplished by using a filter or screen in conjunction with thelamp. Of course, when such filters are used the efliciency of the lampis reduced and in order to avoid this disadvantage resort has been hadto a green fluorescing glass, such as uranium glass, which wasfabricated into a lamp container, or, when a clear glass container wasused, a fluorescent material emitting green colored light, for example,zinc sulphide or zinc silicate, has been associated with the lamp. Whilesuch fluorescing glass or, materials have increased the efliciency ofthe lampthey have not proven entirely satisfactory because they transmita certain portion of the blue colored rays emittedby the mercury vapordischarge which, of course, is a disadvantage when a typical orpuregreen light is desired.

The object of the present invention is to provide a gaseous electricdischarge device which emits typical green light at high efliciencies.Another object of the invention is to provide a method of making a greencolored material which emits green fluorescent light. Still 'i'urtherob- .jects and advantages attaching to the device and to its use andoperation will be apparent to those skilled in the art from thefollowing particular description.

The invention attains its object by associating with the device a greencolored material which emits green colored light, for example, a greencolored zinc sulphide or a green colored zinc silicate coating appliedto either the inner or the outer surface of the container of the device,which material not only emits green light when irradiated by the raysemanating from the discharge but also serves as a filter or screen whichtransmits only the green colored rays emitted by the discharge. Whendesired, the green colored, green fluoresclng material is placed on asupport consisting of a light transmitting material, such as a clearglass support or a celluloid support associatedwith the lamp. A lamphaving this structure is a highly efllcient source of typical greencolored light. It will be understood, or

course, that where fluorescent material emitting rays of another coloris used, such as a material emitting blue rays, the material is coloredblue to screen out the light other than the blue light emitted by thedischarge.

In the drawing accompanying and forming part of this specification agaseous electric discharge lamp embodying the invention is shown in aside elevational partly sectional view.

Referring to the drawing the gaseous electric discharge lamp devicecomprises a tubular container I consisting of the usual containerglasses, such as lead or lime glasses. Said container I has therein astarting gas, such as argon, neon,

or xenon, or a mixture of such gases, and a quantity 6 of vaporizablematerial, such as mercury. An electrode 4 mounted on a current lead 3 issealed into the pinch 2. at each end of said container I. Each of saidelectrodes 4 consists of a pressed and sintered mixture of pulverized,high melting point metal, such as tungsten, and a material having highelectron emissivity characteristics, such as barium oxide, and is heatedto an electron emitting temperature by the discharge incident thereat.

The inner surface of said container I has thereon a coating 5 offluorescent material, such as zinc sulphide or zinc silicate which emitsgreen colored light during the operation of the lamp device. Saidcoating 5 is afllxed to said container I by methods now known in theart, such as by applying .a light transmitting enamel to the innersurface of the container and partly embedding particles of thefluorescent material in said enamel. While these materials are white orslightly yellow in appearance we have discovered that they can be madegreen in appearance to serve as 'a screen or filter for the light otherthan the green light emitted by said discharge by adding theretoa greencoloring material, such as nickel chloride (NiClz) or nickel sulphide(NiS) This green coloring material can also be used in form of a veryfine translucent layer or coating arranged with respect to the directionof rays behind the fluorescent material.

While we have shown and described and have pointed out in the annexedclaims certain novel features of the invention, it will be understoodthat various omissions, substitutions and changes in the forms anddetails of the device illustrated and in its use and operation may bemade by those skilled in the art without departing from the spirit andscope of the invention, for example, sheet metal electrodes which remaincomparatively cool during the operation of the device are used in placeof the thermionic electrodes 4, when desired, or when desired indirectlyheated electrodes, such as the Hull type of electrode is used in placeof said electrodes 4, or, when desired, any of the well known startingelements, such as auxiliary electrodes or electrically conductingstrips, are mounted in said container.

What we claim as new and desire to secure by Letters Patent of theUnited States, is:

1. A gaseous electric discharge lamp device comprising an elongated,tubular container, electrodes sealed therein at the ends thereof, agaseous atmosphere therein emissive in visible light of a plurality ofwave lengths under excitation by an electric discharge between saidelectrodes, a coating of fluorescent material on the wall of saidcontainer surrounding the discharge path between said electrodes, saidmaterial being emissive in visible light of one of the wave lengths ofthe visible light emitted by the gaseous discharge and a coloringmaterial incorporated in said fluorescent material, said coloringmaterial being in the same spectral range as the light emitted by saidfluorescent material to screen out the visible light from the dischargeother than that light of a wave length emitted by said fluorescentmaterial whereby said lamp emits light from both the gaseous electricdischarge and said fluorescent material which is characteristic of saidfluorescent material.

2. A gaseous electric discharge lamp device comprising an elongated,tubular container, electrodes sealed therein at the ends thereof, agaseous atmosphere therein comprising mercury vapor, a green fluorescentcoating of zinc silicate on said container surrounding the dischargepath between electrodes and a green colored composition containingnickel incorporated in said zinc silicate.

3. A gaseous electric discharge lamp device comprising an elongated,tubular container, electrodes sealed therein at the ends thereof, agaseous atmosphere therein comprising mercury vapor, a green fluorescentcoating of zinc sulphide on said container surrounding the dischargepath between electrodes and a green colored composition containingnickel incorporated in said zinc sulphide.

4. A gaseous electric discharge lamp device comprising an elongated,tubular container, electrodes sealed therein at the ends thereof, aquantity of mercury therein the vapor of which is emissive in visiblelight of a plurality of wave lengths under excitation by an electricdischarge between said electrodes, a coating of fluorescent material onthe wall of said container surrounding the discharge path between saidelectrodes, said material being emissive in visible light of one of thewave lengths of the'visible light emitted by the gaseous discharge and acoloring material incorporated in said fluorescent material, saidcoloring material being in the same spectral range as the light emittedby said fluorescent material to screen out the visible light from thedischarge other than that light of a wave length emitted by saidfluorescent material whereby said lamp emits light from both the gaseouselectric discharge and said fluorescent material which is characteristicof said fluorescent material.

OTTO FRITZE. ALFRED RUTTENAUER.

